Hostname: page-component-78c5997874-j824f Total loading time: 0 Render date: 2024-11-05T13:06:06.228Z Has data issue: false hasContentIssue false
  • English
  • Français

Phase Equilibria and Lattice Parameters of Fe2Nb Laves Phase in Fe-Ni-Nb Ternary System at Elevated Temperatures

Published online by Cambridge University Press:  26 February 2011

Masao Takeyama ,
Nobuyuki Gomi ,
Sumio Morita  and
Takashi Matsuo
Masao Takeyama
Affiliation:
Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2–12–1 Ookayama, Meguro-ku, Tokyo 152–8552, JAPAN
Nobuyuki Gomi
Affiliation:
Graduate Student
Sumio Morita
Affiliation:
Graduate Student
Takashi Matsuo
Affiliation:
Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2–12–1 Ookayama, Meguro-ku, Tokyo 152–8552, JAPAN
Get access

Abstract

Phase equilibria in Fe-Ni-Nb ternary system at elevated temperatures have been examined, in order to identify the two-phase region of γ-Fe (austenite) and ε-Fe2Nb (C14). The ε single phase region exists in the range of 27.5 to 35.5 at.% Nb in the Fe-Nb binary system, and it extends toward the equi-niobium concentration direction up to 44 at.% Ni in the ternary system at 1473 K, indicating that more than half of the Fe atoms in Fe2Nb can be replaced with Ni. Thus, the γ+ε two-phase region exists extensively, and the solubility of Nb in γ phase increases from 1.5 to 6.0 at.% with increase in Ni content. The lattice parameters of a and c in the C14 Laves phase decrease with increasing Ni content. The change in a axis is in good agreement with calculation based on Vegard's law, whereas that of c axis is much larger than the calculated value. The result suggests that atomic size effect is responsible for a-axis change and the binding energy is dominant factor for the c-axis change. To extend these findings to development of new class of austenitic steels strengthened by Laves phase, an attempt has been made to control the c/a ratio by alloying. The addition of Cr is effective to make the c/a ratio close to the cubic symmetry value (1.633).

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 842: Symposium S – Integrative and Interdisciplinary Aspects of Intermetallics , 2004 , S5.37
Copyright
Copyright © Materials Research Society 2005

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Masuyama, F., Report of JSPS 123rd Committee on Heat-Resisting Materials and Alloys, 38, 211 (1997).Google Scholar
2. Igarashi, M., Iseda, A. and Kan, T., Report of JSPS 123rd Committee on Heat-Resisting Materials and Alloys, 44, 205 (2003).Google Scholar
3. Kadoya, Y., Report of JSPS 123rd Committee on Heat-Resisting Materials and Alloys, 44, 215 (2003).Google Scholar
4. Takeyama, M., Report of JSPS 123rd Committee on Heat-Resisting Materials and Alloys, 45, 51 (2004).Google Scholar
5. Takeyama, M., Morita, S., Yamauchi, A., Yamanaka, M. and Matsuo, T., Superalloys 718, 625, 706 and Various Derivatives, Eds. by Loria, E. A., TMS, 333 (2001).Google Scholar
6. Takeyama, M., Yokota, H., Ghanem, M. M. and Matsuo, T., Journal of Materials Processing Technology (Proceedings of THERMEC'2000) 117, 3 (2001). [CD-ROM], Session D7.Google Scholar
7. Gomi, N., Morita, S., Matsuo, T., Takeyama, M., Report of JSPS 123rd Committee on Heat-Resisting Materials and Alloys, 45, 157 (2004).Google Scholar
8. Thoma, D.J. and Perepezko, J. H., Journal of Alloys and Compounds, 224, 330 (1995).Google Scholar
9. Chen, K. C., Peterson, E. J. and Thoma, D. J., Intermetallics, 9, 771 (2001).Google Scholar
10. Niessen, A. K., de Boer, F. R., Boom, R., de Chatel, P. F., Mattens, W. C. M. and Miedema, A. R., CALPHAD, 7, 51 (1983).Google Scholar
11. Kaloev, N. I. et al., Russian Metallurgy, Translated from Izvestiya Academii Nauk SSSR, Metally, 202 (1988).Google Scholar